The present invention relates to an ink jet head for use in an ink jet printer and capable of ejecting ink of particular color for forming a color image in combination with other ink jet heads, and more particularly to a structure and a method for mounting an ink jet head. Also, the present invention is concerned with a method and an apparatus for producing an ink jet head assembly.
Today, an ink jet printer capable of forming an image by ejecting ink drops via ejection ports is extensively used because of its low noise, small size configuration. An ink jet printer may be loaded with four ink jet heads each being filled with with one of cyan ink, magenta ink, yellow ink and black ink in order to form a full-color image. Specifically, to form a color image, the ink jet heads are arranged on the printer in an array, and each ejects ink of particular color toward a preselected position of a paper or similar recording medium. The prerequisite with this type of printer is that the four heads be accurately mounted to the printer in order to insure high image quality. If any one of the ink jet heads is deviated from a preselected position in each direction then the ink drop ejected from the head cannot hit a desired position on a paper. This results in color misregister or the deviation of an image with respect to the contour of the paper and thereby deteriorates image quality.
To protect image quality from deterioration ascribable to the positional deviation of the heads, it is necessary that the relative position between the four heads themselves and the relative position between the heads and the paper be fixed with a deviation smaller than preselected one.
While screws are predominant as means for fixing the heads 1a-1d in place, they bring about positional deviation as great as several ten microns to several hundred microns and fail to implement the required accuracy. Although the required accuracy may be available with screws, screws lower the yield and thereby increase the production cost. For this reason, adhesives expected to reduce the deviation, compared to screws, are being tested, as stated earlier. Specifically, adhesive is filled in a gap formed between two objects for positional adjustment (sometimes referred to as fill adhesion). The gap is greater than an adjustment margin.
This kind of approach is taught in, e.g., Japanese Patent Laid-Open Publication No. 7-89185. Specifically, a gap between desired objects is selected such that the objects do not contact each other despite the accuracy of their configurations, and adhesive is filled in such a gap. It has also been proposed to mount an ink jet head to a head holder by using ultraviolet (UV) ray curable adhesive.
However, the conventional fill adhesion schemes are likely to fail to maintain the required positional accuracy of the ink jet head. This reduces the yield and causes the objects with low accuracy to be simply discarded, resulting an increase in production cost. In addition, when the adhesive peels off after the production, the force fixing the head in place decreases and causes the printer to lose its fundamental function.
It is therefore an object of the present invention to provide a structure and a method for mounting an ink jet head capable of mounting the head to an ink jet printer with unprecedented accuracy, increasing yield, and preventing a force fixing the head in place from decreasing after production, and a method and an apparatus for producing an ink jet head assembly.
In accordance with the present invention, a device for ejecting a substance to a desired object includes a plurality of ejecting members for ejecting the substance. A a base holds the plurality of ejecting members. A holding member holds, after the plurality of ejecting members and base each has been adjusted to a respective preselected position, the ejecting members and base between the ejecting members and the base with adhesive.
Also, in accordance with the present invention, a method of fixing to a base an ejection device for ejecting a substance toward a desired object begins with the step of locating the ejection device at a preselected position relative to the base. A fixing device including a first and a second adhering surface applied with adhesive beforehand is positioned such that the first and second adhering surfaces respectively face a mounting surface of the ejection device and a fixing surface of the base. The adhesive is brought into contact with the mounting surface and fixing surface. Then, the adhesive is cured.
Further, in accordance with the present invention, a method of producing an ink jet head assembly including an ink jet head for ejecting ink drops via ejection ports, and a head holder on which the ink jet head is mounted via an intermediate member, the intermediate member being fixed to the ink jet head and head holder by adhesive begins with the steps of chucking the ink jet head, intermediate member and head holder, applying the adhesive to adhering surfaces of at least one of the ink jet head, intermediate member and head holder, and moving each of the ink jet head, intermediate member and head holder to a respective initial adhering position. Each of the ink jet head, intermediate member and head holder brought to the initial adhering positions is adjusted to a respective final adhering position. The intermediate member brought to the final adhering position is released. Then, the adhesive is cured. Finally, the ink jet head is released after curing of the adhesive.
Moreover, in accordance with the present invention, an apparatus for producing an ink jet head assembly includes a head moving mechanism capable of selectively chucking or releasing an ink jet head, for moving the ink jet head to an adhering position and adjusting the position of the head. An intermediate member moving mechanism is capable of selectively chucking or releasing an intermediate member, for moving the intermediate member to the adhering position and adjusting the position of the intermediate member. A head holder moving mechanism is capable of selectively chucking or releasing a head holder, for moving the head holder to the adhering position and adjusting the position of the head holder. An applying device applies adhesive to the adhering surfaces of one of the ink jet head, intermediate member, said head holder. A curing device cures the adhesive. A first sensing device determines that the ink jet head, intermediate member and head holder have been positioned at the adhering position after application of the adhesive. A first releasing device releases the intermediate member moving mechanism from the intermediate member in response to information received from the first sensing device. A second sensing device determines that the curing device has cured the adhesive. A second releasing device releases the head holder moving mechanism from the head holder in response in formation received from the second sensing device.